BE JINN
The grand prizes for the yearly-
software contest will be announced
on Sunday, March 29, at the WACC
Awards Banquet. A thousand dollars
credit towards the purchase of AL-
TAIR equipment will be awarded to
the author of the best "Major Pro-
gram" submitted during the past
year. Another prize of $250 credit
towards the purchase of ALTAIR equip-
ment will be awarded to the author
of the best "Subroutine".
The first annual ALTAIR Software
Contest began in April of 1975.
The first entries were rather scanty,
but as time has gone by, the number
and sophistication of these entries
has increased greatly. The ALTAIR
Software Library is now a very val-
uable resource for ALTAIR users.
Each month during the past year,
MITS has announced prizes for the
best "Major Programs" and the best
"Subroutines". The monthly prize
for the best "Major Program" is $50
credit with a second prize of $25
credit and a third prize of $15 cre-
dit. The author of the best subrou-
tine receives $25 credit with a
second place prize of $15 credit.
Winners of the yearly grand prize
will be selected from these monthly
contest winners, plus late submis-
sions received at MITS before the
convention.
The contest has proved to be an
overwhelming success. The prizes
have motivated ALTAIR users into
building a very substantial soft-
ware library. Needless to say, the
contest will continue for another
year.
MONITOR WINS SOFTWARE CONTEST AGAIN
This month another twenty-two pro-
grams were added to the software
library. And, as usual, there were
very small subroutines (13 bytes) to
large programs (2,125 bytes).
First place program goes to another
monitor program. This one includes
the facility to set break points in
As time draws near, enthusiasm for
the first World Altair Computer
Convention grows. Reservations are
pouring in, and it looks like many
participants will have to stay at
a hotel other than the Airport
Marina because the Marina will pro-
bably be filled. Arrangements for
a second hotel are in progress.
The prize list for the winning de-
monstrations has been announced.
Grand Prize will be an assembled
Altair Floppy Disk Drive and Con-
troller. Second Prize will be an
assembled Altair 8800B with 4.K of
Altair static memory. Third Prize
will be an assembled Altair 16K
Static Memory Card. In addition
to these prizes, a number of door
prizes will be given away at the
Sunday Awards Banquet. Included
are:
1. Vectored Interrupt with Real
Time Clock card (assembled) .
2. PROM memory card (assembled).
3. 88-4PI0 parallel interface
card with 4 ports (assembled) .
4. 88-2SI0 serial interface card
with 2 ports (assembled) .
5. 25 copies of the Microcomputer
Dictionary by Charles Sippl .
6. Several assembled Altair 680's.
7. Direct Memory Access card (as-
sembled).
You must attend the banquet to win
these prizes. Banquet tickets sold
at the door ($10 each) .
For further information, see the ad
on the back page of this issue of
Computer Notes, or contact David
Bunnell at MITS, (505) 243-7821.
a user program. This allows you to
stop a program and print out register
contents and examine memory locations
to verify that the program is per-
forming correctly or figure out why
it isn't. While not as sophisticated
as the break point facility in DBG-
8800, it is still very useful.
Second place major program goes to a
BIOPLOT program, which is perhaps the
most unique entry for the software
contest. This program produces a
graphic plot of what are conjectured
to be three cycles that affect a per-
son's behavior. No matter what the
validity of these cycles turns out
to be, the program demonstrates good
use of plotting techniques.
Third place major program goes to a
LIFE program. In case you don't know
already, LIFE is a game where an ini-
tial matrix of cells changes accord-
ing to an algorithm which either de-
letes or inserts new cells. Certain
patterns of cells repeat, others
disappear, and others "move". This
program displays the changes in the
cell pattern in real time or a TVT-II.
FIRST PLACE MAJOR PROGRAM
#1-21-761
Authors: John Arnold and Dick
Whipple
Length: Approximately 500 bytes
Title: ASCII Monitor/Editor
Following commands are included:
DOP-Dump Octal
LDO-Load Octal
EDT-Change memory
SBP-Set Break Point
CBP-Clear Break Point
XQT- Execute
RDC-Read Data from Cassette
WDC-Write Data to Cassette
RUN-Start user program
CPY- Block memory move
MSG-send characters to output device
— Continued On Page 7 —
CONtt*
FEBRUARY
Vol.l Issue 9
1976
PAGE TOO
COMPUTER NOTES-FEBRUARY n ITPb
by David Bunnell
USERS GROUP NEWS
Now that We Are in the New Building
If you've ever had the opportunity
to move a corporation, you know that
the logistics can be staggering.
And with a business such as MITS,
you can't simply shut down for a few
weeks. You have to continue in oper-
ation.
Considering this, the move to 2450
Alamo went remarkably well. As re-
ported in this column in the last
issue of C. N. ; production, repair,
shipping, and the stockroom were all
moved and in operation before the
rest of the company was moved. The
rest of the company, which consists of
marketing, accounting, administration,
advertising, engineering, and soft-
ware was moved and in semi-full oper-
ation within a two-day period. The
movers had promised that this could
be done in one day, but two days
ain't bad.
Now that we have the facilities to
greatly expand production and to
work more efficiently, the question
is this : Can we meet the ever-ex-
panding demands of our customers?
Time will tell, of course, but I
think the answer is a "qualified"
yes. We get a lot of criticism for
the things we haven't shipped, but
you never hear about the things we
have shipped. The number of Altair
mainframes out in the field, up and
running, is staggering. And the
number of new Altair options is very
impressive. My answer is "qualified"
because virtually everyone in the
micro-computer business has consis-
tently under-estimated the market.
No one can say with much accuracy
how much this market will grow dur-
ing the next year. The end is not
in sight.
One thing that might blow the lid
off is an article in Time Magazine ,
Readers Digest , Playboy , or a re-
port by NBC or CBS news. These
things have been rumored for some
time, and I know for a fact that an
article for Time has been written
and submitted to their editors .
But you know how editors are. Don't
you?
Software in the Hobby Market
By now you may have seen Bill Gate's
"Open Letter to Hobbyists" in one
of the several hobby publications
where it has appeared. (See op-
posite page.) Bill raises a number
of good points, the most crucial of
which is: Will there be good soft-
ware available to hobbyists if
they continue to steal it?
Bill and his crew now have BASIC up
and running for the 6800. Their
8080 BASIC and their Altair Disk
BASIC is phenomenal and who can be-
lieve that companies such as IMSAI
will come up with anything nearly
as good? And for "free", no less.
It's something to think about.
This Month's Issue
This issue of C. N. is limited by
our usual standards due to the move
and to the amount of energy re-
quired to organize the WACC. Miss-
ing is the much -read column by Ed
Roberts, normally positioned on
page 3. But, we'll be back on
track in March.
im
Uf'JBM
M
* >m>: ■> -
i%
, iflMi
(New MITS building in foreground. Airport
Marina Hotel in Background. These buildings
are the sites of the Altair Computer Con-
vention.)
Convention time is approaching and
by now, I hope, all of you have
received our mailing of the schedule
and reservation forms. As we noted
on the prize list, the deadline for
returning the forms was extended to
March 10. If, for some reason, you
are an 8800 owner or user, and you
did not receive the mailing about
WACC, drop me a postcard and I will
send it to you immediately. The
only persons we may have missed are
those who just recently changed ad-
dresses or those who purchased
through a school or company name
and have not sent us the user's
name.
In the October issue of Computer
Notes we accepted a "Roulette" pro-
gram, #912751, into the software
library. This program was sent in
by Gerhald Hansel, and I mistakenly
put Gerhald down as the author. The
program was actually written by
Gerhald' s son, Steven Hansel. "Rou-
lette" has been tested on an IBM
360.
Our Accounting Department has asked
me to mention refunds in this arti-
cle. Customers who have cancelled
an order, or for some reason are
requesting a refund, should receive
their refund within 2 to 3 weeks.
The refund cannot be sent out im-
mediately due to our computer in-
voicing and cancellation system.
Many customers have been ordering
additional copies of BASIC. If you
order a second copy of the same ver-
sion software, you are charged a
copying fee only. If you order an
updated version, you are charged a
copying fee plus the price differ-
ence between versions. Extra op-
tions ordered with software have
additional charges. Please note
on software orders what software you
have previously purchased from MITS,
if any. A few customers have been
accident ly overcharged for 2nd co-
pies because we do not check each
file completely with new orders.
I hope to see all of you at the
World's ALTAIR COMPUTER CONVENTION.
by Barbara Sims
ft
COMPUTER NOTES-FEBRUARY-, lT7b
PAGE THREE
Dear Sir:
While looking through all the
various newsletters, Byte articles,
R adio-Electronics , and Popular Elec-
tronics magazines in an attempt to
interface my ALTAIR 8800 with Don
Lancaster's TVT-1, and that darn
Southwest Tech Products K/E/Y/-
B/O/A/R/D/ that I should never have
bought, but did, I suddenly realized
that your product, the ALTAIR 8800
has come in for quite a bit of crit-
icism.
Since I own one, purchased in
kit form during the $995 "BASIC"
special, and since it is up and
running, I just wanted to tell you
that I feel most of that complaining
is unjustified. I, for one, am a
satisfied owner of the ALTAIR 8800.
I called MITS 3 times while I
was constructing my computer, and
each time all of your employees that
I came in telephone contact with
were very courteous to me and very
helpful . Parts that needed to be
replaced due to defects caused by
your suppliers, not MITS, arrived
within a week, and I am sure that
even though they were sent by first
class mail, most of the short delay
was due to the postal department,
not MITS. You see, they were ship-
ped within 24 hours of my phone calls.
I never got around to sending
my critique of Mike Hunter's MITS
Caravan Presentation ... It was
excellent and he fielded some rather
nasty questions from the session I
attended when he was here in the
Boston area, most of those from
disgruntled 8800 owners who were
having memory problems.
I guess most of the people who
have constructed the 8800 and don't
have it running may have valid com-
plaints for your firm, and your
product. And I will venture a
guess that some of the people who
get your newest baby, the ALTAIR
680, will feel the same way. I,
for one, feel that I received full
value for the money I paid.
I bought it on September 15, 1975,
and as of this date I am satisfied
with your product. It works for me.
I can't ask anything more of it, or
MITS . . . Nor should I expect any-
thing more of it or your company.
Have a nice day.
M. Douglas Callihan
Dear Sirs :
I am a software engineer with
EMC Controls and I have been in-
volved in major software develop-
ment projects for several years.
Many people think that computer com-
panies give software away as in-
ducements to sell their hardware.
This was true in the '60's when IBM
sold systems for millions. But now
that hardware is "cheap", most com-
puter companies realize that soft-
ware is the major cost in selling
systems. I approve and agree with
your statement about your right to
place, what I consider a minimal
charge, on the ALTAIR BASIC you have
developed. More power to you.
W. T. Shaw
AN OPEN LETTER TO HOBBYISTS
To me, the most critical thing
in the hobby market right now is the
lack of good software courses, books
and software itself. Without good
software and an owner who understands
programming, a hobby computer is
wasted. Will quality software be
written for the hobby market?
Almost a year ago, Paul Allen
and myself, expecting the hobby mar-
ket to expand, hired Monte Davidoff
and developed Altair BASIC. Though
the initial work took only two
months, the three of us have spent
most of the last year documenting,
improving, and adding features to
BASIC. Now we have 4K, 8K, EXTEND-
ED, ROM and DISK BASIC. The value
of the computer time we have used
exceeds $40,000.
The feedback we have gotten
from the hundreds of people who say
they are using BASIC has all been
positive. Two surprising things
are apparent, however. 1) Most of
these "users" never bought BASIC
(less than 10% of all Altair owners
have bought BASIC) , and 2) The
amount of royalties we have received
from sales to hobbyists makes the
time spent on Altair BASIC worth
less than $2 an hour.
Why is this? As the majority
of hobbyists must be aware, most of .
you steal your software. Hardware
must be paid for, but software is
something to share. Who cares if
the people who worked on it get paid?
Is this fair? One thing you
don't do by stealing software is get
back at MITS for some problem you
may have had. MITS doesn't make
money selling software. The royalty
paid to us, the manual, the tape and
the overhead make it a break-even
operation. One thing you do do is
prevent good software from being
written. Who can afford to do pro-
fess ibnal work for nothing? What
hobbyist can put 3 man-years into
programming, finding all bugs, doc-
umenting his product and distribute
for free? The fact is, no one be-
sides us has invested a lot of money
in hobby software. We have written
6800 BASIC, and are writing 8080
APL and 6800 APL, but there is very
little incentive to make this soft-
ware available to hobbyists. Most
directly, the thing you do is theft.
What about the guys who re-sell
Altair BASIC, aren't they making
money on hobby software? Yes, but
those who have been reported to us
may lose in the end. They are the
ones who give hobbyists a bad name,
and should be kicked out of any club
meeting they show up at.
I would appreciate letters from
anyone who wants to pay up, or has
a suggestion or comment. Just write
me at 1180 Alvarado SE, #114, Alb-
uquerque, New Mexico, 87108. Nothing
would please me more than being able
to hire ten programmers and deluge
the hobby market with good software.
Bill Gates
General Partner,
Micro-Soft
PAGE FOUR
COMPUTER NOTES-FEBRUARY-, 117b
The Computer Store Microsystems
The Computer Store opened in mid-
March in Burlington, Mass., con-
veniently located near Route 128,
the circumvential highway which em-
braces most of the New England elec-
tronics industry. This pilot loca-
tion is at 120 Cambridge Street,
Burlington, Mass. , 10803, which is
less than a mile north of Route 128,
reached from Exit 41N. The phone
number is (617) 272-8770. Hours
are 9-5 on Mon. - Wed.; 9-9 on Thurs.
- Fri.; and 10-5 on Saturday.
The Computer Store carries an ex-
tensive inventory of all Altair pro-
ducts and has a professional staff
with a full complement of sophisti-
cated equipment to assist in nearly
any hardware or software system pro-
blem. This facility is intended to
provide a full capability for both
the hobbyist and the industrial and
commercial Altair computer user.
If you'd like to LOAD up on some
good INPUT, you should JUMP over to
MICROSYSTEMS and see just how the
Altair computers STACK up. Far from
being a DUMP, it's the place to pick
up a POINTER or two.
What you READ may not always RE-
GISTER, so you should INTERFACE
with the MICROSYSTEMS people to
CLEAR the air about the WRITE sys-
tem for you. It will ADD up to a
smart MOVE so POP on over and PUSH
your way in or give them a CALL and
you'll be sure to COMPLEMENT their
OUTPUT and RETURN again and again.
It won't hurt a BIT!
BYTE!)
(They don't
MICROSYSTEMS
6605A BACKLICK ROAD
SPRINGFIELD, VA 22150
(703) 569=1110
Computer Products Unlimited
4216 West 12th St.
Little Rock, Arkansas 72204
(501) 666-2839
Marsh Data Systems
It's up and running. 8K BASIC is
on display at Marsh Data Systems on
the ALTAIR 8800, and it's a fan-
tastic language we would like every-
one to see. Our address is 5405-B
Southern Comfort Blvd. , Tampa, FL,
33614. Our telephone number is
(813) 886-9890. We are located
near the north west corner of the
Tampa Airport at the intersection
of Hillsborough Avenue and Eisen-
hower Boulevard. Our store hours
are: Noon to 5 p.m. Tuesday
through Thursday and Noon to 8 p.m.
Friday and Saturday.
he shelf
In addition to full support of the
MITS product line, the Computer Store
carries tools and instruments, books
and manuals, selected chips and sup-
port hardware, and is being expanded
to include other supplies and support
equipment to service the entire mar-
ket who purchase the Altair computer
systems, including distribution of
such items as magnetic media (discs,
cartridges) and paper products.
The founders of the "Northeastern"
Computer Stores are Dick Brown and
Sid Halligan, both of whom have had
long and extensive careers in the
mini and micro -computer industries.
Dick, the President, has been Dev-
elopment Manager for Digital Equip-
ment Corporation as well as formerly
being a Vice President/Director of
Control Logic as well as the founder/
President of Computer Guild. Sid,
Vice President, was a founder and
Vice President (Sales) of Prime Com-
puter, Inc., as well as having a
long, successful career in marketing
with Computer Controls Corp. (later
Computer Controls Division of HIS)
both in the United States and Europe.
Other staff members bring heavy tech-
nical backgrounds to support the
sales and marketing expertise.
The "Northeastern" Computer Store is
not corporately related to Dick
Heiser's Computer Store, also known
as Arrowhead Computing, although both
organizations are MITS dealers.
The Computer Store
120 Cambridge Street
Burlington, MA 10803
(617) 272-8770
CPU
CPU (Computer Products Unlimited)
is located at 4216 West 12th St.,
Little Rock, Arkansas, 72204, (501)
666-2839. The owner-manager is
Harry W. Mohrmann, 31, who has a
background in math and physics as
well as six years experience as
manager of a data processing cen-
ter.
With a full-time staff of five, CPU
offers for the hobbyist a complete
line of MITS products as well as tech-
nical books and magazines, electronic
tools, simulation board games, elec-
tronic parts and a work area for help-
ing hobbyists build their kits.
For the businessman CPU installs,
maintains, and programs complete
computer systems for any applica-
tion.
CPU also sells time, by the hour,
on any of their three Altair 8K
BASIC systems that they have avail-
able for playing games or for pro-
gram development.
Store hours are 10 to 6, Monday
through Saturday, and after hours
by special appointment.
CPU is a division of Kay Enterprises,
Inc., which for the past 13 years
has provided customized services for
sales analysis, payroll, accounts
receivable, accounts payable, gen-
eral ledger bookkeeping and software
development.
Marsh Data Systems, owned and oper-
ated by Don Marsh, features the
complete line of ALTAIR products
with both assembled units and kits
available off the shelf. Naturally
advice is available to the kit
builders on assembly of their com-
puter and interface to other de-
vices. Software information is
available as well as suggestions
on standard programming techniques.
This has become a meeting place
for computer hobbyists, where we
all can meet and talk computer.
People like to play with BASIC
(it's better than an electric
train) and once you catch the
fever, it's hard to quit. When
BASIC is in the ALTAIR computer,
it comes alive; and it has a very
nice personality.
Marsh Data is also marketing computer
books and literature. The literature
includes two logic courses (Digital
Logic Without Electronics and Inter-
mediate Logic Diagrams) plus inter-
face instructors for interfacing the
ALTAIR 8800 with the SWTP CT-1024
Video Terminal. Under development
is a Baudot to ASCII translator cir-
cuit for those of you who have Baudot
machines. Our desire is to interface
the ALTAIR 8800 with everything so
the computer can be used with any-
thing that might be available.
Marsh Data Systems
5405-B Southern Comfort Blvd.
Tampa, FL 33614
(813) 886-9890
COMPUTER NOTES-FEBRUARY ■,. 117k
PAGE FIVE
Authoritative, up-to-the minute source of microcomputer terminology
©€OMP
DICTIONARY
The Microcomputer Dictionary & Guide by Charles
J. Sippl fills the urgent need for all computer people,
engineers, scientists, industrialists, communications
people— as professionals, amateurs, teachers, or
students— to become quickly acquainted with the
terminology and nomenclature of microcomputing.
This book contains over 5000 definitions and
explanations of terms and concepts relating to micro-
processors, microcomputers, and microcontrollers.
Its 704 pages also contain appendices on: pro-
grammable calculators; math and statistics definitions;
flowchart symbols and techniques; binary number
systems and switching theory; symbol charts and
tables; summaries of BASIC, FORTRAN and APL.
In addition there is a comprehensive electronics/
computer abbreviations and acronyms section.
Order now and save! Just $15
The Microcomputer Dictionary and Guide normally
sells for $17.95. As a special to the readers of Com-
puter Notes, it is now being offered for $15 (plus $1
for postage and handling}. This offer expires April
15,1976.
Below are some example entries from the Microcomputer Dictionary:
bit — 1 . Bit is an abbreviation for binary digit. Most
commonly a unit of information equalling one binary
decision, or the designation of one of two possible
and equally likely values or states, usually conveyed
as 1 or of anything used to store or convey infor-
mation, (such as 1 or 0, which may also mean "yes' 1
or "no".) 2. A single character in a binary number.
3. A single pulse in a group of pulses. 4. A unit of
information capacity of a storage device. The capacity
in bits is the logarithm to the base two of the number
of possible states of the device.
concatenate — To link together in a series.
cross assembler — 1 . Refers to a program run on one
computer for the purpose Of translating instructions
for a different computer. 2. Programs are usually
assembled by the same assembler or assembly
program contained within or used by the processor
on which they will be run. Many microprocessor
programs, however, are asembled by other
computer processors whether they be standard, time-
shared, mini or other microcomputers. This process
is referred to as cross-assembly, and the programs
are not designed for specific microprocessors but
are to be used on other computers. They are known
as cross-assemblers.
microcomputer — A general term referring to a com-
plete tiny computing system, consisting of hardware
and software, that usually sells for less than $500
and whose main processing blocks are mads of
semiconductor integrated circuits. In function and
structure it is somewhat similar to a minicomputer,
with the main difference being price, size, speed of
execution, and computing power. The hardware of a
microcomputer consists of the microprocessing unit
(MPU) which is usually assembled on a PC board
with memory and auxiliary circuits. Power supplies,
control console, and cabinet are separate.
paging — Refers to a procedure for transmitting
pages of information between main storage and
auxiliary storage, especially when done for the pur-
pose of assisting the allocation of a limited amount of
main storage among a number of concurrently exe-
cuting programs.
parallel input/output card — A typical full parallel
input/output card has the necessary handshake,
flags for conventional parallel interface and con-
tains all required addressing circuitry to allow each
card to be addressed anywhere from location to
location. In some systems both input and output
data have their own 8-bit latch for buffering, in-
cluding necessary logic to allow an adjacent channel
to be a control channel. Thus, adjacent channels can
be used to set up flags and also clear flags and
interrupts.
subroutine — 1. In computer technology, the portion
of a routine that causes a computer to carry out a well-
defined mathematical or logical operation. 2. Usually
called a closed subroutine. One to which control may
be transferred from a master routine, and returned to
the master routine at the conclusion of the subroutine.
3. Refers to either part of a master program or routine
that may be 'jumped' or 'branched' to or to an inde-
pendent program in itself but usually of smaller size
or importance. A. A subroutine is a series of computer
instructions to perform a specific task for many other
routines. It is distinguishable from a main routine in
that it requires as one of its parameters, a location
specifying where to return to the main program after
its function has been accomplished.
transistor-transistor logic (TTL') — This is the most
common form J) IC logic. As a result, the relatively
simple process used to produce TTL logic is a natural
candidate for memory, especially since most mem-
ories are used with TTL logic. However, the TTL
approach— even though the simplest bipolar process
—is considerably more complicated and expensive
than MOS. Since n-channel MOS can now be made as
fast in performance as TTL bipolar, the importance
of the TTL process to the memory market is limited. It
will vie with CMOS for those applications represented
by small memories of around 256 bits per chip, com-
monly intermixed with computer logic (distributed
memory). The only advantage of both CMOS and TTL
in these applications is their 100 percent compatibility
with the logic (i.e., power supplies and signal levels).
Of course, n-channel memories can also be made logic
compatible at lower speed (2 to 3 MHz) operation.
Slightly larger memories can bear the cost of having
less than 100 percent compatibility, so the lower cost
df ^Channel will displace TTL and CMOS in all but
the smallest memories.
testing, microprocessor — Testing microprocessors
presents problems associated with system testing that
are relatively foreign to device manufacturers and
users. As in LSI memory testing, the functional test
pattern cannot be of infinite proportions in length, but
must correlate well with system usage. To do this, a
systems approach is required. For example, it is not
sufficient to use a test pattern derived from logic
simulation. One must test the function of the micro-
processor. For example, if one wishes to test the
arithmetic unit, a simulation of NAN D gate equivalents
is no guarantee that the device will multiply properly.
A realistic test would be to force the device to multi-
ply! The tester is arranged to do this. The micropro-
cessor instructions are loaded in the data buffer
memory which is interfaced to the microprocessor
under test.
A tester, controliing the DBM, presents varied se-
quences of instruction sets to the unit under test. In
this way, the worst case sequence of instructions is
presented to the test device. A microprogrammable
multiprocessor is being used to test a microprocessor.
text editor — A text editor provides the system user
with a convenient and flexible source text generation
system. Source statements are entered via any source
input device/file. The entered source text may be out-
put, statements added, deleted or modified. The text
editor permits the order of statements or groups of
statements to be altered at any time. The final text is
output to a source device/file for use as input to an
Assembler.
wire-wrap advantages — Wire-wrapping offers the
advantage of ease of design, freedom of layout, easy
maintainability and parts replacement, ease of de-
sign change, good performance and good density.
But unless users can justify wire-wrapped intercon-
nection for applications on the basis of economics,
there is no point in using it. Wire-wrapping would
not enjoy its current popularity if it did not offer
economic advantages over other techniques. But it
is also far easier to lay out a wire-wrapped system
than a printed circuit board, and there is also an in-
crease in flexibility of component location. Design
changes can be implemented by documentation
changes. This is considerably easier than modifying
printed circuit artwork and modifying an etched
board when a design change is necessary. Replac-
ing a component is also generally easier in a wire-
wrapped system because of the plug-in feature in-
herent in wire-wrapping hardware. PCB components
can be made pluggable, of course, by the addition
of sockets, but sockets on a printed circuit board
represent additional space, assembly labor and parts
cost.
MAIL THIS SPECIAL COUPON TODAY!
□ Enclosed is check for $_ .
□ BankAmericard # :
□ or Master Charge #_
□ Please send me
-copies of the Micro-
computer Dictionary & Guide at $15 each, plus
$1 postage and handling for each copy.
NAME_
ADDRESS^
CITY
.STATE & ZIP.
L_
MiTS/2450 Alamo SE/Albuquerque, NM 87106
MITS/2450 Alamo SE/Albuquerque, NM 87106/505-243-7821
PAGE SIX
COMPUTER NOTES-FEBRUARY -. 1T?L
SOFTWARE NOTES
Package I has been upgraded in many
ways. And now the machine language
debugger, DBG-8800, -is included as
an integral part of Package I. As
a result of this change, DBG-8800
will no longer be priced separately
from Package I. Instead, Package I
version 3.0 will cost $75 effective
immediately. Users who still have
Package I or DBG-8800 on order will
receive Package I/DBG version 3.0
at no extra charge. All new orders
should be placed at the $75 rate
(cassette or paper tape) . Sale of
the source of DBG-8800 on cassette
or paper tape has been discontinued.
There has been a number of inquir-
ies as to whether DBG-8800 is useful
with BASIC. The answer is no.
ALTAIR BASIC has its own debugging
facilities designed specifically
for debugging BASIC programs.
For those who are interested in more
information on DBG, here is a quick
example:
(underlined typed by user)
DEBUG
1.
$SA10/
NOP MVI B,10Q <LF>
2,
12/
15/
NOP LXI H, #6000 <LF>
3.
NOP MVI M, <LF>
4.
17/
NOP INX H <LF>
5.
20/
NOP DCR. B <LF>
6.
21/
NOP JNZ 15 <LF>
7.
24/
NOP ^X
8.
10G
9. BREAK @24
10. $0AL/ 100 <CR>
11. B/ <CR>
12.
F/ 106! ZP
In the example above, <CR> stands
for carriage return and <LF> for
line feed. What the program does
is zero out the 100 octal locations
starting at location 6000 decimal
(# means decimal - line 2) . After
the program is entered (symbolical-
ly!) a break point is set after the
last instruction (line 7) . Next
execution is begun with a G(G0) com-
mand. When the memory clear program
is done, the break point is hit and
DBG types : the break point number-
and the address of the break point
(line 9) . The user then examines
some registers in octal mode (lines
10 § 11). The user then examines
the flag (condition code) register
and uses the special exclamation
point command to see symbolically
which flags are set.
This is a good example of how short
programs may be "improvised" using
DBG. The monitor program save fac-
ility could be used to save such
improvised programs on paper tape
or cassette..
BASIC NEWS
Disk BASIC is running! Thanks to
many long hours of coding, typing,
and debugging by that microcomputer
programmer par excel lance, Bill
Gates, ALTAIR Disk BASIC has struck
a new high in micro software. As
mentioned before, Disk BASIC has:
Random files
Sequential files
Program saves and load from disk
Program chaining
etc.
We recommend that you have 20K bytes
of memory if you wish to use disk
Extended BASIC. BASIC takes about
15K minimum (can be more depending
on the number of simultaneous ran-
dom and sequential files the user
wants to have open) .
Disk BASIC will always have the cas-
sette and line printer features
built in. (No special versions
should be ordered.) Disk BASIC is
version 3.3 of BASIC. This means
it also has:
Octal constants
Console command
Improved random number generator
Cassette numeric array save/ load
features
and more. These features will not
be available in the 4K, 8K, and Ex-
tended versions (which will stay at
version 3.2), but they will be avail-
able in ROM Extended BASIC.
ROM BASIC?
Yes indeed. No prices or delivery
dates are available, but we will
have BASIC on 12K of ROM. If you
like to power your machine down,
but don't like to reload BASIC
(and can ' t yet afford a disk) , ROM
BASIC is the answer! We will have
more information in coming news-
letters.
For those of you who have left
your fantastic compiler or
whatever waiting in a drawer,
now's the time to get it out!
The yearly grand software prize
($1,000 in credit for ALTAIR
products) will be announced
at the WACC. So dig out that
software and send it in! Today!
Now that Disk BASIC is done, work
on finishing the DOS is underway.
Files are compatible between the
DOS and Extended Disk BASIC--in
fact much of the same code is used.
We now project a delivery date of
the DOS version 1.0 of about April
15.
6800 BASIC
Is finished . . . due to the extra-
ordinary efforts of Richard Wei land
III, the 6800 now has a BASIC com-
parable to the 8080' s. Size: About
6300 decimal bytes. It is so simir
lar to ALTAIR 8K BASIC, the differ-
ences may be summarized on one page .
As those of you who have used 8K
BASIC are aware, it is only 5900
bytes, so the 6800 version is slight-
ly bigger (7%). 8080 addicts that
we were, we expected 'the 6800 ver-
sion to be much bigger. But Ric's
efforts proved convincing. It is
the concensus of most people that
have programmed both CPU's that
while the 8080 can be programmed
in slightly tighter (and tricky)
code, the 6800 is the easier of
the two machines for a beginner to
learn, and requires only slightly
larger memory than the 8080 when
programmed by an expert.
No price for 6800 BASIC has yet
been set.
Please direct any questions you
have about 6800 software to Mark
Chamberlin, our resident 6800 sys-
tems programmer, who is presently
working on the assembler, editor
and monitor.
Direct any 8800 Package I questions
to Paul Wasmund, who rules the
realms of Package I.
SOFTWAR
COMPUTER NOTES-FEBRUARY i n7t
PAGE SEVEN
SOFTWARE CONTEST WINNERS
Continued from Page 1
SECOND PLACE MAJOR PROGRAM
#2-3-761
Author: L. M. Eastburn
Length: 2048 + 77 = 2125 bytes
Title: BIOPLOT
Huge machine language program which
plots graphically on a teletype or
other terminal a person's 23 day
physical § 28 day sensitivity and
33 day cognitive biorhythm cycles.
THIRD PLACE MAJOR PROGRAM
#1-5-761
Author: Adolph P. Stumpf
Length: 247 bytes
Title: LIFE
Plays the game LIFE on a TVT-2, but
can be modified to run on other ter-
minals.
FIRST PLACE SUBROUTINE
#1-15-763
Author: Don Baechtel
Length: 157 bytes
Title: CDUMP
"Core" dump program which dumps
memory in octal and in equivalent
ASCII characters.
SECOND PLACE SUBROUTINE
#2-2-764
Author: M. A. Enkelis
Length: 20 bytes
Title: 16-bit Delay
This subroutine loops for a number
of seconds, minutes and hours--up
to 12 hours.
THIRD PLACE SUBROUTINE
#1-8-761
Author: J. W. Macarty
Length: 32 bytes
Title: String Table Search
Uses a search tree to match a string
against a table of reserved words.
#1-14-761
Author: Mark Prinsen
Length: 324 lines (BASIC)
Title: Stock Market Simulation
Allows up to 10 players to play a
simulated stock market. Slight
changes are necessary to run in
ALTAIR BASIC.
#2-2-761
Author: M. A. Enkelis
Length: 19 lines (BASIC)
Title: Julian Calendar
#2-13-761
Author: Roger Walker
Length: 238 bytes
Title: OCTAL MINI-MONITOR
#1-20-761
Author: Erik T. Mueller
Length: 206 bytes
Title: Number Guessing Game
User must try to guess a number
between and 255. Assumes a TVT-II
is the terminal.
Slot Machine Game
For MITS BASIC
by Jon Walden
This program is written using the combinations and percentages sug-
gested by Donald D. Spencer on pages 219-223 of his book, "Game Playing
with Computers".
SLOT MACHINE IS SET UP WITH 3 REELS, 20 SYMBOLS EACH REEL:
CHERRIES
ORANGES
BELLS
LEMONS
WATERMELONS
BARS
REEL
4
5
4
3
3
1
REEL
6
4
6
2
1
1
REEL
7
5
4
3
1
SYMBOL
1
#
EQUIVALENT
1
2
3
4
5
6
PAYOFFS ARE AS FOLLOWS: (A = ANY SYMBOL)
1
#
+
+
$
COMBINATION
A
1
#
+
+
$
A
A
$
#
$
+
$
PAYOFF
$ 3
5
6
8
10
15
18
20
200
NUMBER OF POSSIBLE WAYS
400
240
20
168
24
3
140
9
1
PAYOFF AVERAGES $70.49 FOR EVERY $80 PUT IN; NET LOSS IS $9.51; THE HOUSE
MAKES 11.89%. (CASINOS ARE THOUGHT TO MAKE BETWEEN 3% AND 50% WITH THE
AVERAGE BETWEEN 11% and 12%).
EACH TIME THE REELS SPIN, YOU ARE BETTING A DOLLAR. THE PROGRAM ES-
TABLISHES THE REEL EQUIVALENTS WITH RANDOM NUMBERS, PRINTS OUT THE SYM-
BOLS, THE PAYOFF (IF ANY), AND SUMMARIZES YOUR FINANCIAL POSITION. AT
THAT POINT. (REMEMBER IF YOUR WINNINGS ARE $20 AND YOU WIN A $5 PAYOFF,
YOUR NEW WINNINGS ARE $24— $25 MINUS THE DOLLAR YOU BET.)
THE PROGRAM IS WRITTEN IN "MITS" BASIC AND USES THE FOLLOWING VARIABLES:
K
L
N
P
Q
R(3)
S(6)
W
X/Y
Z
D$
R$(3)
S$(6)
PAYOFF COUNT
LOSSES (MONEY PUT IN)
NUMBER OF RANDOMS IGNORED
PAYOFF
EQUIVALENT OF ALL THREE REELS
EQUIVALENT OF INDIVIDUAL REELS
SYMBOL EQUIVALENT TABLE
WINNINGS (TOTAL PAYOFFS)
"FOR" LOOP CONTROLLED VARIABLES
IGNORED RANDOMS
DECISION
SYMBOL FOR INDIVIDUAL REELS
SYMBOL TABLE
I'd like to say something brief about MITS Basic: I think it's great!
Comments have been made about it being slow and about certain clumsy
features. But the agility to play with bits, to sense ports and to use
single ASCII codes is long overdue! I hope the use of "INP" in this
program will encourage other programmers to work on new data input
methods (especially for games). Having to "hit return" after each entry
is a drag!
— Continued On Pages —
#1-15-764
Author: Don Baechtel
Length: 13 bytes
Title: MULT
8 bit times 8 bit unsigned binary
multiply.
#1-15-765
Author: Don Baechtel
Length: 57 bytes
Title: MBSHIFT
Shifts up to 64K bytes, up to 25,6
places left or right with zero 1 fill
into the empty positions.
#1-15-766
Author: Don Baechtel
Length: 33 bytes
Title: APTLOAD
Absolute boot loader.
#2-12-761
Subroutines
Author: Sidney Rosell
Length: 45 bytes
Title: Memory Test and Clear Rou-
tine
Simple memory test. Can also be
used to clear memory.
- Continued on Page 8 -
PAGE EIGHT
CONPUTER NOTES-FEBRUARY-, lT?b
Software contest winners
Continued From Page 7
#1-15-761
Author: Don Baechtel
Length: 84 bytes
Title: TAPELOAD
Loads an ASCII octal paper tape into
memory.
#1-15-762
Author: Don Baechtel
Length: 28 bytes
Title: DIV
Divides an 8 bit unsigned binary
number by an 8 bit unsigned bi-
nary number.
#1-22-761
Author: William A. Ruggirello
Length: 106 bytes
Title: 16 Bit divide
Divides a 16 bit unsigned binary
number and rounds up the 16 bit
result.
#1-28-761
Author: Martin H. Eastburn
Length: 48 bytes
Title: Memory Test
Simple memory test by another member
of that prolific group of program-
mers, the Eastburn family.
#2-2-763
Author: M. A. Enkelis
Length: 7 lines (BASIC)
Title: Pseudo Random Number Gen-
erator
Generates a 16 bit pseudo random
integer.
#1-23-761
Author: Harold A. Corbin
Length: 310 bytes
Title: Paper tape Editor
This editor allows corrections to be
made to a line as it is typed in,
and automatically adjusts input
fields on each line to satisfy the
input field requirements for a
multi pass 8080 assembler.
#2-2-762
Author: M. A. Enkelis
Length: 76 lines (BASIC)
Title: LUNAR LANDER
Game to simulate landing of lunar
module on the moon.
#2-5-761
Author: George W. Rompot
Length: 49 bytes
Title: ASCII Keyboard Load
Loads OCTAL data through a keyboard
into memory.
PACKAGE I REVISED
by Paul Wasmund
For all faithful users of Package
I, we have some great news. The
finishing touches are being put
on Revision 3.0 of this package
and it really looks great. Just
to start with, the DEBUG package
is now included with Package 1.
The other big news is the Monitor.
It now supports all MITS 1/0 boards,
has a built in console command and
has some minimal debugging features
built into it. To give you an idea
of the improvements, here is a list
of the new commands:
NUL - Causes nulls to be written
after a carriage return.
CMS - Console command.
EXM - Prints contents of memory
locations in octal.
DEP - Deposits octal constants
in memory.
DMP - Dumps absolute programs
from the monitor
JMP - Jumps to any location in
memory.
The Package I manual has also been
improved, making it easier for be-
ginners to read and understand.
This is hoped to be the last major
revision of Package I. The only
new releases will be to fix bugs
that may be found. If you do find
anything you think is a software
bug, please send me an output de-
monstrating the problem if possible.
Slot Machine Game
100 DATA =,0,1,#, + ,$
110 FORX=1 T0 6:READS$(x):S(X) = X:NEXT
120 IFNOT(INP(0)<128)G010 120
130 OUT 1,12
140 PRINT 1AB(6);"»»» SLOT MACHINE«««":PRINT:PRINT
150 N = INT(500*RND(8))+1
FORX = 1 10N:Z = RND(8):NEXT
PRINT "PRESS THE SPACE BAR TO GET REPEATED"
PRINT "REEL SPINS. (EACH SPIN COSTS YOU $1 .)"
PRINT:PRINT "PRESS 'Q' WHEN YOU'RE READY TO QUIT."
PRINT:PRINT "PRESS ANY OTHER KEY TO GIVE YOURSELF"
PRINT "A BREAK. THE SPACE BAR WILL GET YOU"
PRING "GOING AGAIN . . . GOOD LUCK! !!"
IF NOT (INP(1 ) = 32 ORINP (1 ) = 81 ) GOTO 230
IF1NP(1) = 81 GOTO 750
L=L+1
FOR X = 1 TO 3:R(X) = INT(20*RND(8)) + 1 :NEXT
IFR(1)<6THENR(1) = 2:GOTO330
IF R(1 )<1 THEN R(1 ) = 1 :GOTO 330
IF R(1 )<t 4 THEN R(1 ) = 3:GOTO 330
IF R(1 K1 7 THEN R(1 ) = 4:GOTO 330
IF R(1 )<20 THEN R(1 ) = 5:GOTO 330
R(1) = 6
IFR(2) 7THENR(2) = 3:GOTO390
!FR{2) 13THENR(2)=1:GOTO390
IFR(2) 17 THEN R(2) = 2:GOTO 390
IFR(2) 19THENR(2) = 4:GOTO390
IF R(2) = 1 9 THEN R(2) = 5:GOTO 390
R{2) = 6
IF R(3) < 8 THEN R(3) = 2:GOTO 440
IF R(3)<1 3 THEN R(3) = 3:GOTO 440
IF R(3)<1 7 THEN R(3) = 4:GOTO 440
IF R(3)<J 9 THEN R(3) = 5:GOTO 440
R(3) = 6
Q=100*R(1)+10*R(2) + R(3)
IF Q = 666 THEN P = 200:GOTO 550
IF Q = 555 THEN P= 20:GOTO 550
IF Q = 222 THEN P= 18:GOTO550
IF Q = 556 THEN P= 15:GOTO550
10:GOTO550
8GOTO550
6:GOTO 550
5:GOTO550
3:GOTO550
Continued From Page 7
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
510
520
530
540
550
560
570
580
590
600
610
620
630
IFQ = 444THENP =
IFQ = 332THENP =
FQ = 226 THEN P =
IFINT(Q/10)=11 THENP--
IFINT(Q/100)=1 THEN P =
P =
FOR X = 1 TO 3:FOR Y = 1 TO 6
IFR(X) = S(Y)GOTO580
NEXTY
R$(X) = S$(Y):NEXTX .
W = W + P:IFP = GOTO 610
K=K+1
PRINT:PRINT"REELS:"TAB(9);R$(1);TAB(12),R$(2);TAB(15);R$(3)
IF P = GOTO 700
IF P = 200 GOTO 660
640 IFNOT(INP(0)<128)GOTO640
650 OUT 1 ,7:PRINT "PAYOFF: $",P:GOTO 700
660 FOR X = 1 TO 75
670 IFNOT(INP(0)<128)GOTO670
680 OUT 1,7:NEXT
690 PRINT "JACKPOT!! !!!! $";P
700 ON SGN(W-L) + 2 GOTO 710,720,730
710 PRINT "SO FAR YOU'VE LOST $";L-W:GOTO 740
720 PRINT "SO FAR YOU'RE EVEN ":GOTO 740
730 PRINT "SO FAR YOU'VE WON $";W-L
740 PRINT:GOTO230
750 PRINT:PRINT "TIMES PLAYED: ";L:PRINT "NUMBER OF PAYOFFS: ";K
760 PRINT "AMOUNT PAID: $";W
770 ON SGN(W-L) + 2 GOTO 780, 790,810
780 PRINT "TOTAL LOST: $":L-W:PRINT "WANNA TRY AGAIN, SUCKER?" :GOTO 9999
790 PTINY "YOU BROKE EVEN. TOO BAD,":PRINT "THE NEXT ONE MIGHT HAVE"
800 PRINT "BEEN THE BIG ONE' ":GOTO 9999
810 PRINT "TOTAL WON: $":W-L:PRINT "YOU BUY THE DRINKS!"
9999 END
OK
Reprinted from the February, 1976, issue of Interface Magazine.
COMPUTER NOTES-FEBRUARY-. JT?L
PAGE NINE
Vector Interrupt an
by Annette Mil ford
Two new MITS products, the 88-Vector
Interrupt (88-VI) and the optional
88-Real Time Clock (88-RTC) are now
being shipped to customers. Although
both of these peripherals have been
designed on the same printed circuit
board, the Vector Interrupt may be
purchased without the Real Time Clock.
The 8800 can be hardwire connected
for a maximum of one interrupt system.
This means, of course, that it is not
possible to wire an I/O board for sin-
gle level interrupt and connect the
88-VI for multi-level interrupt.
VECTOR INTERRUPT
The interrupt service routine for
level 2 would appear as follows:
OCTAL LOCATION INSTRUCTION
20
PUSH B
21
PUSH D
22
PUSH H
23
PUSH PSW
24
JMP LEV2
NOTE: As soon as the interrupt RST
instruction is executed, interrupts
are automatically disabled.
A software device called the inter-
rupt service handler, supervises
eight interrupt service routines,
thereby enabling the interruption of
a lower interrupt routine by a high-
er one and also insuring that each
lower routine is returned to and
fully executed.
The RST instruction saves the current
program counter in the stack, then
branches to the appropriate location
(0, RST 0; 10, RST. 1; 20, RST 2; 30,
RST 3; 40, RST 4; 50, RST 5; 60, RST
6; 70, RST 7). The correct inter-
rupt service routine saves all CPU
registers on the stack, then, if
required, jumps out of the RST loca-
tion to complete the rest of the
program.
As an independent board, the 88-VI
has been designed to increase the ef-
ficiency of your system. It is use- LEV2
ful in real time applications, when
it is necessary to service 1/0 de-
vices on a priority basis. Specifi-
cally, the VI provides the 8800 with
the capability to interrupt activity,
via the Restart (RST) instruction
and to allow only the highest active
priority of eight levels to inter-
rupt the 8800. A system which in-
cludes the Floppy Disk, a teletype,
a line printer and an 88-VI, for
example, should service the Floppy
Disk before any other device.
Placing the Floppy Disk at the
highest priority on the 88-VI then,
insures that the software necessary
to process data is available to the
ALTAIR 8800 as soon as possible.
The ENABLE INTERRUPT instruction of
the 8800 permits the 88-VI to inter-
rupt. After each interrupt from the
88-VI is completed, ENABLE INTERRUPT
is activated again, thereby reacti-
vating the 8800' s internal interrupt.
The RST instruction translates in OFF:
octal code to 3A7; and "A" translates
into a 3 bit code which represents BOTH:
one of the eight priority locations:
0, 10, 20, 30, 40, 50, 60, or 70
(octal). Restart instructions, then,
are RST = 307, RST 10 = 317, RST
20 = 327, etc., (octal) .
LDA
CURLEV
PUSH
PSW
MVI
A,15Q
STA
CURLEV
ORI
300Q
OUT
3760
EI
DI
POP
STA
ORI
OUT
POP
POP
POP
POP
EI
RET
PSW
CURLEV
300Q
376Q
PSW
H
D
B
;GET LEVEL INTERRUPTED
;SAVE OLD LEVEL ON STACK
;SET CURRENT LEVEL
;OR IN BITS REQUIRED BY VI BOARD
;0RI 330Q SHOULD BE SUBSTITUTED
;IF THE RTC IS HOOKED TO THIS LEVEL
; DEVICE SERVICE ROUTINE
;G0ES HERE
;P0P OLD INTERRUPT LEVEL
; RESTORE CURLEV
;"0R" IN BITS FOR VI
;TELL VI BOARD WHAT LEVELS TO ACCEPT
; RESTORE ALL REGISTERS
; ENABLE THE INTERRUPTS
; RETURN FROM INTERRUPT
Continued On Page 12—
HARDWAR
PAGE TEN
COHPUTER NOTES-FEBRUARY-, ]fl7h
by Bill Kuhn
the VLCT with 4PI0
In answer to questions about use of
the VLCT with the 4-PI0, we have
made the following hookup and tested
it.
GENERAL PROCEDURE:
First: Decide what section of
the 4-PI0 port you will use for the
various signals necessary.
Second: Make an interface
cable (25 pin male to 25 pin female)
to connect the 4-PI0 to the proper
lines on the VLCT (or if you haven't
wired your VLCT you can wire its
connector and eliminate the extra
cable.)
Third: Initialize the port
so it is ready to send and receive
on the proper sections.
Fourth: Design and run a test
program to check steps 2 and 3.
HERE'S WHAT WE DID
1. We chose section A of the
4-PI0 for input data lines, and
CA1 as our flag for data ready at
the input lines.
We chose section B for output
data lines and CB1 as our signal
from the VLCT requesting new data.
CB2 was chosen as the signal to
the VLCT that new data was ready
at its inputs.
2. We made an interface cable
as shown in the following chart:
NOTE: If you haven't wired your
VLCT, you may wire its connector
the same as the 88-4PI0 connector
and eliminate the interface cable.
88-4PI0 Signal Name Connector Pin # Connector Pin # VLCT Signal Name
PA
4
5
D0
PA 1
5
6
D0 1
PA 2
14
7
D0 2
PA 3
15
8
D0 3
PA 4
16
1
D0 4
PA 5
17
2
D0 5
PA 6
18
i
3
D0 6
PA 7
19
4
D0 7
CA 1
2
10
READY OUT
CA 2
3
not used
PB
20
14
DI
PB 1
21
15
DI 1
PB 2
22
16
DI 2
PB 3
23
17
DI 3
PB 4
25
21
DI 4
PB 5
25
20
DI 5
PB 6
10
19
DI 6
PB 7
11
18
DI 7
CB 1
12
23
READY KEY
CB 2
13
22
DATA READY IN
Ground
6
13
Ground
r 9
RESET IN
Us
BUSY OUT
NOTE 2: We also tied Pin 9 to Pin 25 on the VLCT end of our cable to
accomplish the following:
— Continued on Page n —
Computer Clubs
Amateur Computer Group of
New Jersey
Sol Libes
(201) 889-2000 (day)
277-2063 (eve)
George Fischer
(212) 351-1751
Amateur Computer Society
260 Noroton Ave.
Darien, CT 06820
Atlanta Area Microcomputer
Hobbyist Club
Jim Dunion
421 Ridgecrest Rd.
Atlanta, GA 30307
(404) 373-8990
Bit User's Association
5010 4th Ave. S.
Minneapolis, MN 55408
CACHE
PO Box 36
Vernon Hills, IL 60061
Canadian Computer Club
G. Pearen
861 11th St.
Brandon, MB, Canada
(204) 725-1079
Chicago Area Microcomputer Users
Group
Bill Precht
1102 S. Edson
Lombard, IL 60148
Computer Hobbyist Group of
North Texas
8 2377 Dalworth 157
Grand Prairie, TX 75050
Bill Fuller
(214) 641-2909
Neil Ferguson
(817) 461-2867
Lannie Walker
(817) 244-1013
Computer Hobbyists of Santa
Barbara
131 Santa Ana Place
Santa Barbara, CA 93111
Denver Amateur Computer Society
PO Box 6338
Denver, CO 80206
HP-65 Users Club
Richard J. Nelson
2541 W. Camden PI.
Santa Ana, CA 92704
Homebrew Computer Club
Robert Reilling,
193 Thompson Square
Mountain View, CA 94043
Miami Area Computer Club
Terry Williamson
PO Box 430852, S.
Miami, FL 33143
Micro- 8 Computer User Group
Cabrillo Computer Center
4350 Constellation Rd.
Lompoc, CA 93436
— Continued On Page 15 —
COMPUTER NOTES-FEBRUARY-. lT?b
PAGE ELEVEN
New Audio Modulation Method for ACR
As evidence that we at MITS listen
to our customers, we are improving
the 88-ACR read and write perfor-
mance. The changes described below
will allow the 88-ACR to accept 2.75
times wider speed variation when de-
modulating tapes written with the
new method. Also, demodulation
(reading) of tapes written by the
old method will be the same as be-
fore.
I Purpose : Make reading and
writing of data on audio tapes
less susceptible to errors due
to speed variations, and to
make adjustment of R29 (phase
locked loop center frequency
adjust) less critical.
II Method : Change modulator fre-
quencies from 2225Hz/2025Hz-
(200 Hz difference) to 2400Hz/
1850Hz- (550 Hz difference).
This change keeps the center
frequency at 2125Hz, allowing
the 88-ACR to demodulate (read)
either type of modulation.
VLCT
BUSY is low active and goes low after
DATA READY IN goes high only for the
time constant determined by the One
slot in the VLCT Receiver. As long
as RESET -(BUSY) is high, the sequence
generator of the VLCT send section
will not count. The result is that
after entering three key strokes, the
READY OUT goes low signaling the 4-PI0
that DATA is ready. Your software
should send the received data back to ,
the VLCT for verification. No new
data will be transmitted till the VLCT
receives data back. (See "Using the
VLCT", Computer Notes, Vol. 1, Issue
5.)
— Continued From Page !0 —
3. We used the same initializa-
tion program contained in the 4-PI0
manual with the following changes.
Loc. 15 005
Loc. 21 055
Disables CA2, sets CA1
low active, and enables
it (bit 7 becomes our
DATA READY flag).
Same as in manual ex-
cept CB2 set when next
"E" pulse goes high
instead of when CB1 is
active.
4. Our test program is as fol-
lows:
Loc.
1
2
3
4
5
6
7
10
11
12
13
14
15
Octal
333
020
346
200
312
xxx
xxx
333
021
323
023
303
xxx
xxx
Mneumonic
INPUT
address
ANI
data
JZ
<b2>
<b3>
INPUT
address
OUTPUT
address
JMP
<b2>
<b3>
Read A Control Register
Mask for bit 7 (data ready flag)
Test and loop if (Loc. 0) not present
Input data
Output data
(Loc. 0)
When this program is run, the follow-
ing should happen: after you enter
3 keystrokes, the octal number should
appear at the DATA IN display on the
VLCT and should remain until you en-
ter another 3 keystrokes.
If that works, you are all set.
Talk to your computer!
Ill Modifications to 88-ACR Modem
Boards in the field:
A) Modulator - Change jumpers
as follows:
1. Remove jumpers #1 § 2.
2. Connect pins 3, 4, and
5 of IC "J" together.
3. Change jumper #3 from
3B to 2A.
4. Change jumper #4 from
4B to 4A.
5. Disconnect pins 5 and
6 of IC "K" from ground
(unsolder and bend out
of board) .
6. Connect pins 4 and 5
of IC "K" together.
7. Change jumper #5 from
5B to 2A.
8. Connect pin 6 of IC "K"
to point 5A.
9. Change jumper #7 from
7B to 7A.
NOTE: The "B" row of jum-
per points is closest to
edge of Modem Board, the
"A" row of jumper points
is closest to the row of
numbered jumper wires
(see schematic diagram
in manual) .
This changes the modulation
frequencies to:
LOGIC 1 = 2404 Hz +_ 1. Hz
LOGIC = 1852 Hz + 1 Hz
(measured at IC "H"-8)
B) Demodulator : Change R28
to 3.3K ohms, or parallel
a 5.6K ohm resistor with
the existing 8.2K ohm re-
sistor.
This change increases the
lock range of the phase
locked loop (IC "C") for
the wider frequency spread
of the new modulation me-
thod. It does not affect
demodulation of tapes pre-
viously recorded with the
old frequencies (2225/
2025 Hz).
This change allows tape
speed variations between
writing and reading of
over 3% without readjust-
ment of R29 (if demodu-
lating tapes written with
the new method) .
IV Other Circuitry Changes Re-
commended for the 88-AC R.
A) Change C18 (was 5 yf
electrolytic) to a 1 yf
mylar or non-polarity
sensitive capacitor.
This prevents breakdown
of CI 8 when reverse biased
(no carrier) . j
— Continued On Page 13 —
PAGE TWELVE
COMPUTER NOTES-FEBRUARY-. ]fl?b
— Continued From Page 9 —
During this program, the following
occurs;. The previous interrupt le-
vel (in CURLEV) is saved on the
stack. The current interrupt level
is output to the VI board in order
to prohibit interrupts at level 2
or levels of any lesser priority-
fin this case, 3, 4, 5, 6, or 7)
from interrupting. The current
interrupt level is saved in CURLEV.
Interrupts are then re -enabled to
allow execution of higher priority
interrupts. At this point, the
appropriate device service routine
should be executed. After the ser-
vice routine is completed, inter-
rupts are disabled. The previous
interrupt level, saved in CURLEV
is re-stored in CURLEV and output
to the VI controller. The regis-
ters are then popped off of the
stack, interrupts are reenabled,
and the interrupt service routine
returns .
The interrupt routine is the same
for all interrupt levels, except
for instruction 3 (MVI). The fol-
lowing chart indicates the correct
MVI instruction for each of the
eight interrupt levels. Level
is the highest priority interrupt
level, and level 7 is the lowest.
Note also that instruction 5 re-
quires that 330 be substituted for
300 if the RTC is hooked to this
level, thereby allowing the RTC
to interrupt when serviced.
REAL TIME CLOCK
The Real Time Clock is designed for
the computer system in which timing
of events is critical. An interrupt
is generated by the 88 -RTC after a
precise interval of time, thereby
enabling software to time certain
routines and even to generate the
correct time, day, and year upon
request.
The 88-RTC provides the option of
one of two sources, a derivative
of the 2 megahertz clock or the ;
line frequency. Both sources offer
respective advantages. The 2 mega-
hertz clock should be used in sys-
tems that demand a fast RTC; it is
selectable for time intervals down
to every 100 microseconds. The
line frequency (60 Hertz) on the
other hand, is efficient in systems
that depend upon accuracy over a
long period of time. Power com-
panies constantly adjust frequency,
thus insuring a consistent source.
The table below shows the frequency
and associated time interval for
both sources at each of the four
selectable divide rates:
A JMP instruction must be put
at location 70, so that the in-
terrupt will cause a JMP to the
machine language interrupt res-
ponse routine. Correct branching
is implemented by the following
three BASIC commands:
POKE 56,195
POKE 57,187
POKE 58,31
The following commands allow the
USR function to turn on the clock
and to enable interrupts. This
changes the JMP FCERR in location
72 to a JMP INIT (see symbol
table) .
POKE 73,250
POKE 74,31
Interrupt
Level
RST Address
Instruction
MVI A,17Q
1
10
MVI A,16Q
2
20
MVI A,15Q
3
30
MVI A, 140
4
40
MVI A,13Q
5
50
MVI A,12Q
6
60
MVI A,11Q
7
70
MVI A,10Q
SOURCE
DIVIDE
DIVIDE
TIME
RATE
FREQUENCY (HZ)
INTERVAL
Line Frequency (60 Hertz)
1
60
16.67 milli-
seconds
10
6
166.7 milli-
seconds
100
.6
1 . 67 seconds
1000
.06
16.67 seconds
10,000 Hz (a derivative
of the 2 MHz system clock)
1
10,000
100 microseconds
10
1,000
1 millisecond
100
100
10 milliseconds
1000
10
100 milliseconds :
Note that this time interval repre-
sents the frequency at which the
88-RTC will cause an interrupt. For
example, if 1000 Hz is selected, the
RTC will generate an interrupt every
1000th of a second or 1000 interrupts/
second.
In order to set the time, make
these commands. (Note: Set the
time a few minutes ahead to allow
for the time necessary to type
the commands) :
POKE 8180, TIM (60ths of a second)
POKE 8181, TIM (seconds)
POKE 8182, TIM (minutes)
POKE 8183, TIM (hours)
The above commands could also be part
of a BASIC program which asked for
the initial tie as HHMMSSJJ (hours,
minutes, seconds and jiffies — 1
jiffy = 1/60 second).
MITS has developed a machine lan-
guage program for the 88-RTC, which
keeps track of hours, minutes, se-
conds, and 60ths of seconds in four
consecutive memory locations. This
program uses 8K BASIC, a USR assem-
bly language subroutine, and an
interrupt response subroutine. To
execute the program, strap the RTC
for line frequency in f 1, and load
the following program using Package """See Program on Page 13 -
I (assembler, editor, monitor) .
Note that Q represents octal.
After the program is loaded, BASIC
must be loaded into the CPU. The
"memory size" question in BASIC'S
initialization's dialog should be
answered with 8122. All other ini-
tialization questions in BASIC should
be answered as usual.
After initialization, certain modi-
fications to BASIC must be made.
ACR
— Continued From Page 11 —
B) Use the old C18 (5 yf
electrolytic) to add a
5 yf capacitor: + end
to IC "C" pin 9 end of
R30, -- end to -12 volts.
This helps stabilize ad-
justment of R29.
C) Change R32 to 8.2K (use
old R38) and change Zl
(12 volt zener) to a
3.3K resistor. This
allows the P. L. L. out-
put (IC "C", pin 8) to
pull down point "RS" to
a valid logic even if
the system negative vol-
tage supply is low.
D) Remove diode D4. This
allows reading and writ-
ing of tapes simultan-
eously.
E) Optional - For indication
of the carrier (2K Hz
tones) a L. E. D. may be
wired to points "A" and
"K" on the Modem Board.
Remove the jumper wire
from "A" to "K", and
connect the LED anode
to "A", the cathode to
"K". When the carrier
is being received, the
LED forward current is
about 10MA. Use a red
LED only--1.7 volts for-
ward drop.
Effective Date of Change
A),, All CQMTER II units, all i
assembled 88-ACR' s and
all repaired 88-ACR' s
shipped from MITS after
March 1, 1976, contain
the modification des-
cribed above.
B) All 88-ACR kits shipped
after March 15, 1976,
contain the modification
described above.
C) All ALTAIR BASIC and Pack-
age I cassette tapes will
be made with the new modu-
lation technique starting
April 5, 1976.
VI Converting Old Tapes to the
New Modulation Method :
Although it is not necessary,
you may wish to convert exist-
ing tapes to the new form. To
do this, you need two tape re-
corders and :
A) Modify your 88-ACR board
as indicated, including
Step IV-D.
B) Identify the slower of the
two tape recorders, and
use it for playback of
your existing tape during
transfer. The play machine
should be slightly slow to
prevent the inputting of
data faster than it can be
outputted. Connect the
slower machine to the "PLAY
IN" circuit, and adjust
R29 for the proper pattern.
ORG
START: PUSH
PUSH
PUSH
LDA
PUSH
MVI
STA
ORI
OUT
EI
MVI
LXI
LOOP: MOV
INR
SBI
JNZ
MOV
INX
DCR
JNZ
MOV
INR
SBI
JNZ
MOV
OUTLP: DI
POP
STA
ORI
OUT
POP
POP
POP
EI
RET
NMB: ' DS '"
CURLEV: DB
INIT: MVI
OUT
EI
LAST: RET
END
17673Q
PSW
B
H
CURLEV
PSW
A,10Q
CURLEV
330Q
254
B,3
H,NMB
A,M
M
59
OUTLP
M,A
H
B
LOOP
A,M
M
23
OUTLP
M,A
PSW
CURLEV
300Q
254
H
B
PSW
5
A,360Q
254
TIM
UNDEFINED SYMBOLS
SYMBOL TABLE
$0200000
START 017673
CURLEV 017771
NMB 017764
LOOP 017721
OUTLP 017746
INIT 017746
INIT 017772
LAST 017777
Program for RTC
Continued From Page 12 —
; PROGRAM STARTS AT THIS MEMORY LOCATION
; STACK ALL REGISTERS TO BE USED
;PICK UP OLD LEVEL NUMBER
;SAVE IT ON THE STACK
;NEW LEVEL IS 10Q
; STORE THIS AS THE NEW CURRENT LEVEL
;0R IN BITS NEEDED TO RESET RTC AND VI BOARD
; OUTPUT LEVEL INFO TO VI BOARD
;GET ADDRESS OF 60TH'S OF SECONDS COUNTER
;PICK UP COUNTER
INCREMENT COUNTER
; CHECK IF COUNTER IS NOW = TO 60
;IF < 60 WE ARE DONE
;IF = 60 ZERO OUT COUNTER
; POINT AT NEXT COUNTER
DECREMENT NUMBERS OF COUNTERS LEFT TO CHECK
;L00P TILL 60TH'S, SECONDS, AND MINUTES ARE DONE
;NOW CHECK HOURS COUNTER
;MAKE SURE NOT MORE THAN 24 HOURS
;POP OLD INTERRUPT LEVEL OFF STACK
; STORE AGAIN AS CURRENT LEVEL
;OR IN CONTROL BITS FOR VI
; OUTPUT CURRENT LEVEL TO VI BOARD
; RESTORE ALL REGISTERS USED
;RETURN TO INTERRUPTED PROGRAM
INITIALIZE THE VI BOARD
EXAMPLE: If the RTC were to be set
for 9:30 a.m., the commands
would appear as follows:
POKE 8180,0
POKE 8181,0
POKE 8182,30
POKE 8183,9
4. In order to start the clock, type:
A •* USR (1)
A printout of the correct time will be
received when the following BASIC pro-
gram is typed in.
10
20
30
40
50
RUN
A9a: A3@
DIM Z(3)
FOR X=l TO 3
Z(X)=PEEK(8180+X)
NEXT X
PRINTZ(3);":";Z(2);":";Z(1)
A9A: A30A:A0
— Continued On Page 15 —
PAGE FOURTEEN
COMPUTER NOTES-FEBRUARY-. ITPL
Altair 8800 Interfaces
ALTAIR fifiQQ INTERFACE— THANKS TO
PROFESSOR KENNETH B. UIBERG OF
YALE UNIVERSITY
Altair 8800 Interfaces
One of a kind interfaces are
most conveniently made by wire
wrapping, and wire wrapping tools
are available at a reasonable price.
Most wire-wrap boards are made by
inserting wire-wrap IC sockets into
a suitable board and making connec-
tions on the reverse side. This is
inconvenient for two reasons. First,
each module will then take two loca-
tions on the Altair mother board.
Seconds it is much easier to wire
wrap on the front side of the board
(where the IC's can be seen) than
on the reverse.
The MITS prototype board can
be converted into a wire-wrap board
by soldering IC sockets into the
places provided, and inserting Vec-
tor T-44 mini-wrap terminals from
into the holes connec-
socket pins. The ter-
be soldered from the
These terminals just
holes provided. Up to
For those who construct I/O
boards, an interface which will dis-
play the contents of
is convenient. Such
is shown in Fig. 1 .
377 is decoded by the
the accumulator
an interface
The address
74L30, and
the back side
ting with the
minals should
reverse side,
fit into the
16 sixteen-pin
sockets may be
plus 4 fourteen-pin
placed on the board.
70
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the output is ANDed with S0UT and
PWR by the 74L10. The strobe sig-
nal is inverted by a 7404 (which
will drive the 7474' s) and is used
to latch the data on the bus in
the 7475 latches. Their output
are decoded by the 7447' s and dis-
played using 7 segment LED units.
The contents of the accumulator
are displayed by including
OUT 377
in a program.
In some of our applications, we
wish to read data from BCD coded
switches. Since the 8080 allows a
large number of 1/0 addresses, it is
convenient to read the contents of
each switch using a unique address.
As shown in Fig. 2, this can easily
be done using a 74L30 to decode the
four more significant address bits
along with SINP_j_ and two 74L10 gates
to AND A3 (or A3) with the output
of the 74L30 and PDBIN and select
one of two 74L42. The 74L42's de-
code the three least significant
address bits when enabled, giving
eight possible strobe pulses from
each. A given strobe pulse (neg-
ative going) is used to enable
-Continued On Page 15-
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COMPUTER NOTES-FEBRUARY-, 117b
PAGE FIFTEEN
ACR
— Continued From Page 13 —
C) Connect the other tape re-
corder to the "RECORD OUT"
circuit and use it for re-
cording the new tape.
D) Use the following program
to transfer data:
Address
Octal Code
Mnemonic
000,000
333
IN
1
006
2
017
RRC
3
332
JC
4
000
5
000
6
333
IN
7
007
10
323
OUT
11
007
12
303
JMP
13
000
14
000
E) Start the record machine
first, then start play
machine; then play pro-
gram to transfer data.
F) After your tape has been
transferred, check it for
correct data. If your
playback tape recorder was
too fast, then there will
be bytes dropped.
G) Once your tapes have been
transferred, R29 will pro-
bably not require readjust-
ment. This is one of the
advantages of spreading
the modulation frequencies.
If you have only one tape recorder,
or if the above procedure does not
work for you, read the old tape into
memory, then write it out to tape.
Use the 88-ACR read/write programs
listed in the Nov/Dec COMPUTER NOTES,
pages 22 § 23. If you are rerecord-
ing an ALTAIR BASIC cassette, the
test byte must be changed to 175
for version 3.1 and 256 for ver-
sion 3.2.
If you need to order parts for the
modification, order:
2 ea. 102085 3.3K resistor
1 ea. 100363 l.Omf mylar
capacitor
The cost of parts + postage §
handling is $5.00.
OOPS!
Additions/Corrections
88-4PI0
1. Pin 6 on the 25-pin female con-
nectors is GROUND [this is not
shown on the schematic) .
2. Error on page 6 of the Theory
of Operation Manual. In the
table at the bottom of the page
(setting up C2 to act as an in-
put], right-most column labled
"IRQ". Change Bit 7 to Bit 6 in
both the second line and the
fourth line.
88-2SI0
a) If the Data Ca rrier Detect and
Clear to Send inputs are not be-
ing used, they must be jumpered
to Ground.
b) When using the 2SI0 board to con-
nect a device that is to be used
for loading MITS software, start
the bootstrap loader before
starting the loading device (pa-
per tape reader, etc.).
ALTAIR MDQ INTERFACE
— Continued From Page 14-
four 8T97 gates which are connected
to the corresponding switch. Up to
16 BCD switch (16 integers) can be
read in using this one interface.
Similarly, BCD data may be
displayed using 7 segment units via
the interface shown in Fig. 3.
Here, the three 74L20 gates perform
the high order address decoding
function, enabling one of the 74L42
decoders. The strobe signals may
be used to latch data into one of
several TIL 308 display units (or
the corresponding combinations of
latches, decoders and 7 segment
displays). The data are buffered
by 74L04 and 7406 inverters in order
to have sufficient drive to handle
up to 16 TIL 308's.
COMPUTER CLUBS
— Continued From Page 10 —
Nashua NH Computer Club
Dwayne Jeffries
San Diego Club
181 Cypress Ln.
Garry Mitchell
Nashua, NH 03060
Box 35
Chula Vista, CA 92012
New England Computer Club
c/o BYTE Magazine
Southern California Computer Society
Peterborough, NH 03458
PO Box 987
South Pasadena, CA 91030
New York City Micro
Hobbyist Group
29 Palms California Area Group
375 Riverside Dr. , IE
Sgt. Wesley Isgrigg
New York, NY 10025
74055 Casita Dr.
29 Palms, CA 92277
Pacesetter User's Group
(714) 367-6996
1457 Broadway, Rm. 305
New York, NY 10036
UCLA Computer Club
3514 Boelter Hall
People's Computer Company
UCLA
PO Box 310
Los Angeles, CA 90024
Menlo Park, CA 94025
Universe Unlimited
Pittsburgh Area Computer Club
User's Group
Eric Liber
John E. Kabat
400 Smithfield St.
11918 Forrest Ave.
Pittsburgh, PA 15222
Cleveland, OH 44120
412-391-3800
216-781-9400 Ext. 55
412-276-6546
216-795-2565
Sacramento Minicomputer Users Group
PO Box 741
Citrus Heights, CA 95610
DDDQls
PAGE SIXTEEN
COMPUTER NOTES-FEBRUARY-. ITTb
Altair 4K Sta
Altai? 4K Static from MITS is unquestionably the finest 4K
static memory available anywhere. It is also the fastest.
Altair 4K Static uses Intel 2102 A-4 memory chips which have
a worst case access of 450 nanoseconds at 70 °C. At normal system
temperatures the access times are typically less than 300 nano-
seconds.
Altair 4K Static is fully isolated from the system bus by
Schmitt™ Triggers. Thus, the excessive capacitive loading caused
by other 4K static memories is eliminated. Use of these triggers
on all Altair 4K static inputs greatly reduces noise. Internal data
collection nodes also use Schmitt Triggers, which prevents internal
data bus noise from being transmitted to the system data bus.
Altair 4K Static is the only 4K static supported by MITS.
Owners of Altair 4K Static are eligible to qualify for discounts
on AltairBASICand other MITS products.
Altair 4K Static is the only 4K static that comes with al! the
required Altair hardware including edge connectors and card
guides.
Altair 4K Static is the answer for Altair owners who need
static memory for special applications such as the TV Dazzler
from Cromemco.
PRICES:
Altair 4K Static Kit $159
Altair 4K Static Kit with 2K Memory $134
Chip set to convert 2K to 4K $ 45
SPECIAL— Altair Documentation Notebook. Contains catalog,
price sheet, Computer Notes newspaper, Software Information
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Altair dealers, list of computer clubs, survey of home computing
market, and much more. All in top quality three ring binder.
Only $5 plus $1 for postage and handling. Offer expires April 30,
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CITY __.
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Prices, delivery and specifications subject to change.
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COMPUTER NOTES-FEBRUARY -i n?t.
PAGE SEVENTEEN
LiunJOS
The people who design and manufacture Altair Computer Products.
2450 Alamo SE Albuquerque, NM 87106
505-243-7821
PAGE EIGHTEEN
COMPUTER NOTES-FEBRUARY n lT?b
BASIC language was chosen for the Altair 8800 because it is the easiest
language to learn and because it can be used for an infinite number of
applications. Literally hundreds of thousands of BASIC programs have
been written and are in the public domain. These programs include ac-
counting programs, business programs, scientific programs, educational
programs, game programs, engineering programs, and much more.
Altair BASIC is an interactive language. This_ means that you get im-
mediate answers and you can use your Altair as a super programmable
calculator as well as for writing complicated programs.
8K BASIC Features
Altair 8K BASIC leaves approximately 2K bytes in an 8K Altair for
programming which can also be increased by deleting the math functions.
This BASIC is the same as the 4K BASIC only with 4 additional
statements [ON. . . GOTO, ON . .GOSUB, OUT, DEFj, 1 ad-
ditional command [CONT] and 8 additional functions [COS, LOG,
EXP, TAN, ATN, INP, FRE, POSj. Other additional features include multi-
dimensioned arrays for both strings and numbers, AND, OR, NOT
kk I've seen and used other BASICs, hut byte-for-byte, Altair
is the most powerful BASIC foe seen. I'm particularly im-
pressed with the n-dimensionai arrays (and for strings
too!}, machine level I/O, and machine language Junction
features. The level of your documentation is, for me,
though the high point Sections for those who know
nothing and sections for those who know a lot, plus sec-
tions that 'normaf people can read and understand. w
^:^-mM^ -^ :rJ. .Scott- Williams
Bellingham, Washington
Altair BASIC was written as efficiently as possible to allow for the max-
imum number of features in the minimum amount of memory. You can
order one of three Altair BASICs: 4K BASIC-designed to run in an Altair
§800 with as little as 4K of memory, 8K BASIC, or EXTENDED BASIC
(12K). Each of these BASICs allows you to have multiple statements per
line (a memory saving feature), and each of them is capable of executing
700 floating point additions per second!
The 8K BASIC and EXTENDED BASIC have multi-dimensioned
arrays for both strings and numbers. This is particularly useful for
applications requiring lists of names or numbers such as accounting
programs, inventory programs, mailing lists, etc.
The 8K BASIC and EXTENDED BASIC also have an OUT and cor-
responding INP statement that allows you to use your Altair 8800 control
low speed devices such as drill presses, lathes, stepping motors, model
trains, model airplanes, alarms, heating systems, home entertainment
systems, etc.
Altair BASIC comes with complete documentation including a copy of
"My Computer Likes Me When I Speak in BASIC" by Bob Albrecht, a
beginner's BASIC text.
Never before has such a powerful BASIC language been
marketed at such low prices!
4K BASIC Features
Altair 4K BASIC leaves apporimxately 750 bytes in a 4K Altair for
programming which can be increased by deleting the math functions. This
powerful BASIC has 16 statements [IF. . THEN, GOTO, GOSUB,
RETURN, FOR, NEXT, READ, INPUT, END, DATA LET, DIM, REM,
RESTOR, PRINT, and STOP] in addition to 4 commands [LIST, RUN,
CLEAR, SCRATCH] and 6 functions [RND, SQR, SIN, ABS, INT and
SGN]. Other features include: direct execution of any statement except
INPUT; an"C« " symbol that deletes a whole line and a "^-"that deletes
the last character; two-character error code and line number printed when
error occurs; Control C which is used to interrupt a program; maximum
line number of 65, 535; and all results calculated to at least six
decimal digits of precision.
operators that can be used in IF statements or forumlas, strings with a
maximum length of 255 characters, string concatenation (A$ = B$) and
the following string functions: LEN, ASC, CHAR$, R1GHT$, LEFT$,
MID$, STR$, and VAL.
EXTENDED BASIC
Altair EXTENDED BASIC is the same as 8K BASIC with the addition
of double precision arithmetic, PRINT USING and disk file I/O. A
minimum of 12K memory is required to support EXTENDED BASIC.
Other Altair 8800 software includes a Disk Operating System,
assembler, text editor, and system monitor. Altair users also have access to
the Altair Library, which contains a large number of useful programs.
SOFTWARE PRICES:
Altair 4KBASIC $150
Purchasers of an Altair 8800, 4K of Altair memory,
and an Altair I/O board $ 60
Altair 8K BASIC $200
Purchasers of an Altair 8800, 8K of Altair memory,
and an Altair I/O board $ 75
Altair Extended BASIC $350
Purchasers of an Altair 8800, 12K of Altair memory,
and an Altair I/O Board $150
Altair PACKAGE ONE (assembler, text editor,
system monitor) $ 175
Purchasers of an Altair 8800, 8K of Altair memory,
and an Altair I/O board $ 75
Altair Disk Operating System $500
Purchasers of an Altair 8800, 12K of Altair memory,
Altair I/O and Altair Floppy Disk $150
Note: When ordering software, specify paper tape or
cassette tape.
COMPUTER NOTES-FEBRUARY t n?b
PAGE NINETEEN
A MITS Alt air Computer Report
Technology of Three Altair
Computers
MITS Altair Computers are built
around recently developed "micro-
processor" integrated circuits. These
compact, wafer shaped "chips" are
about 2 inches long, 1/2 inch wide,
and 1/16 inch thick. They represent
over 10,000 electronic components,
and they contain all the logic circuitry
of a full-blown computer.
1. The Altair 8800 Computer is an
"open-ended" general purpose com-
puter built around the 8080 micro-
processor chip. Its basic configura-
tion includes a CPU (Central
Processing Unit) circuit board, front-
panel control board, power supply,
and case. Up to 16 circuit boards can
be added inside the computer simply
by plugging them in. These boards
could include a wide variety of
memory boards, interface boards,
and processor option boards.
The Altair 8800 Computer can be
programmed from the front panel
indicator lights (LED's) and switches,
or it can be interfaced to any number
of computer peripherals. These
peripherals include teletypewriters,
line printers, floppy disks, paper tape
reader/punch, CRT terminals, and
more.
Since the Altair 8800 can be con-
figured to meet the needs of the user,
its applications are virtually unlimited.
2. The Altair 680 Computer is built
around the 6800 microprocessor
chip. It is smaller and more compact
than the Altair 8800, measuring just
11 inches wide by 11 inches deep by
4-11/16 inches high.
While the Altair 680 was designed
primarily for dedicated programming
—such as industrial process control,
several hundred Altair 680's have
been sold to hobbyists for experi-
mentation. One reason for this is that
the Altair 680 is a complete com-
puter in itself. Its main component
board contains the CPU, 1,024 words
of memory (RAM), a PROM monitor
for loading paper tapes and an I/O
port that can be wired for one of four
different types of peripherals. Like
the Altair 8800, it too can be pro-
grammed from the front panel.
3. The Altair 8800B Computer,
MITS' newest computer, is basically
a second generation design of the
Altair 8800. This machine incorpo-
rates some of the most recent
advances in computer technology.
More information can be obtained
from the factory.
The Advent of the Computer Club
Since the introduction of the
Altair 8800 Computer in January of
1975, computer clubs have been
springing up across the country. The
largest of these, the Southern Cali-
fornia Computer Society, now has a
membership of over 2000.
Computer clubs are groups of indi-
vidual computer owners who meet
regularly to discuss mutual problems
and carry out joint projects. In addi-
tion to using computers for tradi-
tional applications such as computer
games, computer art, and educa-
tional programming, many computer
hobbyists are experimenting with
more bizarre applications. These
applications include voice input/out-
put and biofeedback controlled
peripherals.
The Computer as a Household Pet
One computer hobbyist has an
Altair based computer, named Ralph,
which he regards as a household pet.
Besides being inexpensive to feed
and care for, Ralph can perform a
number of entertaining and practical
tricks. These include playing black-
jack, balancing a checkbook, teach-
ing basic mathematics, turning on
the coffee pot in the morning, con-
trolling the temperature and humidity
of the house, flipping on the yard-
lights at dusk, and acting as a burglar
alarm if need be.
Computer Costs
Altair computers, marketed in both
kit and assembled units, have helped
to bring about drastic cuts in the
price of computing. The Altair 680,
for instance, is currently selling for
$345 in kit form. A complete Altair
8800 system with 16K of memory, a
floppy disk, Teletype, and Extended
BASIC language software sells for
under $4,000.
These low costs have opened the
doors to thousands of individuals
and small businesses. And they have
made it practical to use the computer
for a wide range of new applications.
Altair Customers
While the majority of Altair owners
have some sort of technical back-
ground, they include a broad range
of people from engineers to retail
managers to artists, teachers, doctors,
editors, housewives, musicians, lab
technicians, businessmen, attorneys,
and factory workers. In addition to
some of the above mentioned appli-
cations, they are using their Altairs
for such applications as medical elec-
tronics, instrument control, model
train and airplane control, text edit-
ing, mailing list maintenance, soft-
ware development, music synthesis,
interface to larger computers,
graphics display, OSCAR tracking,
bookkeeping, and timeshare services.
More Information
Space does not permit us to pre-
sent a complete discussion of low-
cost computing here, but we have
prepared a complete Altair documen-
tation notebook for those of you who
wish to investigate the matter further.
This notebook includes a catalog of
all Altair products, technical litera-
ture, a more complete discussion of
the home computer, a list of com-
puter clubs, a list of authorized Altair
dealers, a sample Altair Computer
Notes newsletter, and much more in
a sturdy 3-ring binder. Until April 30,
1976, it will sell for $5 plus $1 for
postage and handling.
m
DuQGlB®
Altair Coupon
□ Please send me a copy of your Altair Documentation Notebook.
Enclosed is $5 plus $1 to cover postage and handling.
□ Please send me a free catalog
□ Enclosed is a check for $
□ BankArnericard # □ or Master Charge #_
NAME
ADDRESS
CITY
STATE & ZIP_
MITS/2450 Alamo SE/ Albuquerque, NM 87106/505-265-1951
L. . ' . _J
MITS/2450 Alamo SE/A!buquerque s NM 87106/505-265-1951
PAGE TWENTY
COMPUTER NOTES-FEBRUARY-, lT?b
First Annual
WWIL „ .. t-d Ji^^si ^3 fc ^©£1 i^ £i ^0i
if
This year's most exciting computer convention
could very well be the First Annual WORLD ALTAI R
COMPUTER CONVENTION. Computer hobbyists
from all over the World will gather in Albuquerque,
New Mexico on Saturday and Sunday, March 27 &
28. Many of them will be bringing their Altair sys-
tems in order to compete for the $10,000 worth of
Altair equipment to be given away at the convention.
In addition to demonstrations of Altair product
applications, there will be FOUR SEMINARS pre-
sented during this dynamic weekend.
SEMINAR ONE will be a seminar on LOW
COST COMPUTING conducted by some of the
leading figures in the field. A preliminary list of
speakers includes Larry Steckler, technical editor
of Radio Electronics, Carl Helmers, editor of Byte
magazine, Art Childs, editor of Interface magazine,
David Ahl, publisher of Creative Computing, Judge
Pierce Young, president and founder of the Southern
California Computer Society, and Terry Silver, also
of the SCCS. And this is only the beginning.
SEMINAR TWO will be a complete discussion
of ALTAIR PRODUCTS and Altair design philosophy.
Speakers will include H. Edward Roberts, president
of MITS, Inc.; Project Engineers Bill Yates, Bob
Zaller, Tom Durston, and Pat Goding; Software
Writers Paul Allen and Bill Gates; and Computer
Notes editor, David Bunnell.
SEMINAR THREE will be a presentation of the
updated MITS TRAVELING SEMINAR presented
by Pat Ward. Altair technical binders will be given
away free to people attending this seminar.
SEMINAR FOUR will be an organizational meet-
ing of the Altair Users Group conducted by Barbara
Sims and David Bunnell. Topics will include organi-
zation of the Users Group and ways to improve
MITS service to Altair users. All seminars will be
opened to the audience for questions.
Attendance to the WORLD ALTAIR COMPUTER
CONVENTION will be free to all Altair owners
and out of town guests. The convention will be
held at the new MITS building at 2450 Alamo SE,
within walking distance of the Albuquerque Airport
Terminal. The entire Airport Marina Hotel has been
reserved for this occasion. Reservations at this
hotel (which is also within walking distance of
MITS and the Airport Terminal) can be made by
filling out the coupon in this ad and returning it
prior to February 26. Cost of reservations are $20
per night for a single and $24 for a double.
$10,000
MITS will be presenting door prizes and prizes
for the best demonstrations at the convention.
These prizes will include Altair 8800's, Altair 680's,
and related equipment of a retail value not less
than $10,000. To enter in this contest or to have a
booth at the convention, you must fill out an official
application form from MITS, Inc. Rules and regula-
tions governing demonstrations and booths are
available with application forms.
ALTAIR CONVENTION COUPON
Mame <
Address-
City
State & Zip
□ Yes, I plan to attend the first annual WACC to be held in
Albuquerque, New Mexico on March 27 and 28, 1976.
□ Please reserve a room for me at the Albuquerque Marina
Hotel. I will 'need a □ single □ double room. I plan on staying
in Albuquerque the following nights: □ Friday D Saturday
□ Sunday.
□ Please send me the official entry form for the Altair Demon-
stration Contest.
M1TS/2450 Alamo SE/Albuquerque, 87106 505-262-1951
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